Community-Acquired Pneumonia

Community- Acquired Pneumonia from Sun YaiCheng

Community-Acquired Pneumonia

NEJM 2014;370:543-51.

DIAGNOSIS

1. Evidence of infection (fever or chills and leukocytosis)
2. Signs or symptoms localized to the respiratory system (cough, increased sputum production, shortness of breath, chest pain, or abnormal pulmonary examination)
3. New or changed infiltrate on CXR

Three Decisions

1. Choice of antibiotic therapy
2. Extenting testing to determine the cause of the pneumonia
3. Location of treatment (home, inpatient floor, or ICU).

Choice of Antibiotic Therapy

1. The key to appropriate therapy is adequate coverage of Streptococcus pneumoniae and the atypical bacterial pathogens (mycoplasma, chlamydophila, and legionella).
2. For outpatients, the coverage of atypical bacterial pathogens is most important, Macrolides, doxycycline, and fluoroquinolones are the most appropriate agents.
3. For patients admitted to a regular hospital unit, guidelines from the Infectious Diseases Society of America and the American Thoracic Society (IDSA-ATS) recommend first-line treatment with either a respiratory fluoroquinolone (moxifloxacin 400 mg qd or levofloxacin 750 mg qd) or the combination of a 2nd or 3rd generation cephalosporin and a macrolide.
4. S. pneumoniae remains the most common cause of severe CAP requiring ICU admission, combination therapy consisting of a cephalosporin with either a fluoroquinolone or a macrolide is recommended.

Timing of Initiation of Therapy

1. The IDSA–ATS guidelines do not recommend a specific time to the administration of the first antibiotic dose but instead encourage treatment as soon as the diagnosis is made.
2. An exception is made for patients in shock; antibiotics should be given within the first hour after the onset of hypotension.

Criteria for Health Care-Associated Pneumonia

Original criteria*

• Hospitalization for ≥2 days during the previous 90 days
• Residence in a nursing home or extended-care facility
• Long-term use of infusion therapy at home, including antibiotics
• Hemodialysis during the previous 30 days
• Home wound care
• Family member with multidrug-resistant pathogen
• Immunosuppressive disease or therapy†

Pneumonia-specific criteria‡

• Hospitalization for ≥2 days during the previous 90 days
• Antibiotic use during the previous 90 days
• Nonambulatory status
• Tube feedings
• Immunocompromised status
• Use of gastric acid suppressive agents

* Original criteria are from the IDSA–ATS.
† This criterion was not included in the original criteria but
is frequently included in many studies of health care–associated pneumonia.
‡ Pneumonia-specific criteria are from Shindo et al.

Empirical broad-spectrum therapy with dual coverage for Pseudomonas aeruginosa and routine MRSA coverage has therefore been recommended for patients with risk factors for health care-associated pneumonia.
Another group of patients at risk for pathogens resistant to the usual antibiotics for CAP are those with structural lung disease (bronchiectasis or severe COPD) who have received multiple courses of outpatient antibiotics; the frequency of P. aeruginosa infection is particularly increased in this population.

Hospital Admission

Pneumonia Severity Index (PSI)   NEJM 1997; 336:243-50

CURB-65 Scores   Thorax 2001. 56 S4: IV1–64.

1. Confusion
2. BUN ≥ 20
3. Respiratory rate ≥30
4. SBP < 90 or DBP < 60
5. Age ≥65 years

ICU Admission

IDSA-ATS Guidelines    Clinical Infectious Diseases 2007; 44:S27–72
Minor criteria

1. Respiratory rate≧ 30 breaths/min
2. PaO2/FiO2 ratio< 250 
3. CXR: Multilobar infiltrates 
4. Confusion/disorientation 
5. BUN > 20 mg/dL
6. Leukopenia (WBC< 4000)
7. Thrombocytopenia (platelet< 100,000)
8. Hypothermia (core temperature< 36 ºC)
9. Hypotension (SBP< 90 mmHg) requiring aggressive fluid resuscitation

Major criteria

1. Invasive mechanical ventilation
2. Septic shock with the need for vasopressors

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【摘要小結】
Community- Acquired Pneumonia 社區型肺炎

1. 抗生素選擇：cover Strep. pneumoniae & atypical pathogens

• 門診病人：macrolides, doxycycline, fluoroquinolones
• 住院病人：moxifloxacin 400 mg qd or levofloxacin 750 mg qd 或 2, 3代 cephalosporin 加 macrolide
• MRSA pneumonia 高風險病患：vancomycin 加 linezolid or clindamycin

2. 住院指標

• Pneumonia Severity Index (PSI)：效度較高，需電腦計算分數
• CURB-65 Scores：五項符合三項-->住院，簡單易記
• IDSA-ATS Guidelines：minor criteria 九項符合三項-->住 ICU